In order to achieve high power output levels, laser modules should be supplied with high currents. It is therefore advantageous to connect the laser modules in series to an electrical power supply. The current is consequently the same for all laser modules. The voltages are cumulative. However, connection in series can have the disadvantage that, when one module fails, the other modules also fail at the same time.
In some cases, the laser modules may not only fail completely but their power can also be reduced due to degradation to such an extent that they must be replaced. It is therefore advantageous to measure the optical power of the individual modules in order to be able to determine which modules have to be replaced.
There are generally provided to this end current, voltage, temperature and cooling water throughflow measuring devices for the individual laser modules in order to determine the optical power which generally corresponds to the electrical power minus the thermal power. It is consequently possible to determine a degradation of the laser module in a more or less precise manner.
However, the electrical and thermal power measurement of each laser module within a laser system can be very cost-intensive. Without these measuring devices, however, determining the degradation of the individual laser modules without removing them from the laser system may not be possible. Removing individual modules from the laser system for measurement can itself be time and cost-intensive.